1. Field of Invention
The present invention relates to a bending die having surface microstructures and a bending punch thereof, and more particularly to a bending die in which microstructures are disposed on a surface of a working portion of a bending punch and on a forming surface of a die and a bending punch thereof.
2. Related Art
In the recent decade, with the rapid development of the electronics industry, the sales of commodities like consumer electronic products such as mobile phones and notebook computers increase significantly. These commodities tend to become small in volume, light in weight, high in strength, and high in heat dissipation performance in recent years, which require that the components thereof also need to be made of metal and in miniature sizes. However, component production adopting semiconductor or unconventional processes is subject to disadvantages such as high equipment cost, limited materials used in processes, small depth-to-width ratios of products, and difficulties in making components of 3D shapes.
Metal forming processing is a key technology for mass production of metal parts in conventional manufacturing, which has advantages such as high production efficiency, material saving, high precision, near net shape production, desirable mechanical properties of finished products, unlimited material applications, and simplified design of parts, and meets the conceptual requirements for environmental friendliness of green industries, so that the applications of metal forming in component microfabrication have drawn more and more attention, which is called metal micro-forming.
Bending processing in metal forming processing refers to that metal sheets are bent and plastically deformed into demanded shapes and angles through processing of bending tools. When external forces are removed, the bent, permanent deformations are still kept. FIG. 1A to FIG. 1C are schematic views of a common bending die of a V-shaped bending type and a stamping process thereof. For a bending die 10, a blank 11 (for example, a metal sheet) is first placed on a forming surface 121 of a die 12 and then a bending punch 13 is performed a back and forth stroke towards a die 12 to stamp the blank 11, so that after the blank 11 is pressed and bent, the bottom surface of the blank 11 is shaped by the forming surface 121, and the top surface of the blank 11 is shaped by the bending punch 13, so as to obtain a demanded V-shaped shape finished product or semi-finished product.
In addition, FIG. 2A to FIG. 2C are schematic views of a common bending die of an L-shaped bending type and a stamping process thereof. For a bending die 10′, a blank 11′ first is placed on a forming surface 121′ of a die 12′ a blank holder 14 is positioned and held the blank 11′ and then a bending punch 13′ is performed a back and forth stroke towards the die 12′ to stamp the blank 11′, so that after the blank 11′ is pressed and bent, the bottom surface of the blank 11′ is shaped by the forming surface 121′, and the top surface is shaped by one side of the bending punch 13′, so as to obtain a demanded L-shaped finished product or semi-finished product.
Further, FIG. 3A to FIG. 3C are schematic views of a common bending die of a U-shaped bending type and a stamping process thereof. For a bending die 10″, a blank 11″ first is placed on a forming surface 121″ of a die 12″, and then a bending punch 13″ is performed a back and forth stroke towards the die 12″ to stamp the blank 11″, so that after the blank 11″ is pressed and bent, the lateral surface of the blank 11″ is shaped by the forming surface 121″, the bottom surface of the blank 11″ is shaped by a blank protrusion plate 15 of a protrusion mechanism (not shown), and the top surface is shaped by the bending punch 13″, so as to obtain a demanded U-shaped shape finished product or semi-finished product.
After the bending dies 10, 10′, and 10″ are performed bending and stamping processing on a blank, without causing a crack on the bending corner of the blanks 11, 11′, and 11″, after the blanks 11, 11′, and 11″ are removed from the bending dies 10, 10′, and 10″, a deformation phenomenon of springback inevitably occurs to the bending, causing a change in the size of the finished product and in consequence unable to meet the standards. Therefore, it is usually necessary to perform techniques such as secondary shaping and processing to make the bending angle accurate.